The present invention relates to a suspension cross member of an automotive vehicle which supports vehicle wheels, and particularly to a suspension cross member in which a foaming agent is provided.
Conventionally, technology that the foaming agent is provided in the suspension cross member (a sub-frame) is known, as disclosed in, for example, Japanese Patent Laid-Open Publication No. 04-90974. According to this publication, sympathetic vibrations of a vehicle body can be prevented from occurring by the structure disclosed therein.
Herein, it may be preferable that the foaming agent be provided at only appropriate portions of the suspension cross member, instead of being provided at its whole portions, from viewpoints of its costs itself or manufacturing costs. Also, the suspension cross member may be required to be made with a relatively high rigidity, in order to prevent vibrations transferring from the vehicle wheels to the vehicle body so as to improve the silent ride, or to increase the rigidity of the suspension itself so as to ensure the stable maneuverability of the vehicle. Meanwhile, the suspension cross member may also be required to be made so as to properly absorb an impact caused when the vehicle crashes against an obstacle, thereby reducing the crash impact of the vehicle. Conventional suspension cross members, however, could not improve the impact absorption properly, increasing the rigidity thereof, with the foaming agents appropriately provided therein.